Pyreverse complaining even after having Graphviz

As mentioned in comments by @KanwarG the solution is to install Graphvis from as a proper package and not using the python package found using pip.

If using a mac then a solution is to used Homebrew. If you do not have Homebrew then follow these instructions to install it. Then it is easy to install Graphviz using the following command.

brew install graphviz

If you are using ubuntu Debian the following command is likely to work.

apt-get install graphviz

Hope this helps other people trying to find a solution.

In Windows, the easiest way is to use the Windows equivalent of Homebrew, the package manager Chocolatey. Once you have that installed:

choco install graphviz

It worked out for me on windows by installing Graphviz from their website. Then I added C:\Program Files (x86)\Graphviz2.38\bin to the "Path" environment variable (so the "dot" command is recognized by windows) :